Energy Flow

Sun Light Sunlight is the main energy source for all life on Earth. What % of the sun’s energy is used by living things? Less than 1% of all the sun’s energy that reaches the Earth is used by living things.

Producers / Autotrophs Organisms that can produce their own food source. Producers use sun light or chemical compounds to synthesize their own food.

Producers / Autotrophs Only plants, some algae, & certain bacteria can capture energy from sunlight or chemicals. Use energy from the environment to fuel the assembly of simple inorganic compounds into complex organic molecules. These organic molecules combine to produce living tissue.

Main Autotrophs Plants – on land Algae – in fresh water, and the top layer of the ocean. Cyanobacteria – wet lands and salt marshes.

Photosynthesis Plants use sunlight to convert carbon dioxide (CO2) and water into oxygen (O2) and carbohydrates. Photosynthesis is responsible for removing CO2 from the atmosphere, and replenishing O2.

Chemosynthesis The conversion of energy from inorganic chemicals to organic compounds. Chemosynthesis is performed by several types of bacteria. These bacteria make up a large portion of autotrophs.

Consumers/Heterotrophs Acquire their energy from other organisms. Many diff types of heterotrophs. Herbivores – eat plants Carnivores – eat animals Omnivores – eat both plants & animals

- Ex. Earthworms & maggots 5. Decomposers – break down organic matter 4. Detritivores – feed on plant and animal remains and other dead matter. - Ex. Earthworms & maggots 5. Decomposers – break down organic matter - Ex. Bacteria & fungi DETRITIVORES AND DECOMPOSERS. In the case of a food web, something interesting happens with regard to energy efficiency as soon as we pass beyond carnivores and omnivores to the next level. It might seem at first that there could be no level beyond carnivores or omnivores, since they appear to be "at the top of the food chain," but this only illustrates why the idea of a food web is much more useful. After carnivores and omnivores, which include some of the largest, most powerful, and most intelligent creatures, come the lowliest of all organisms: decomposers and detritivores, an integral part of the food web. Decomposers, which include bacteria and fungi, obtain their energy from the chemical breakdown of dead organisms as well as from animal and plant waste products. Detritivores perform a similar function: by feeding on waste matter, they break organic material down into inorganic substances that then can become available to the biosphere in the form of nutrients for plants. The principal difference between detritivores and decomposers is that the former are relatively complex organisms, such as earthworms or maggots. Both decomposers and detritivores aid in decomposition, a chemical reaction in which a compound is broken down into simpler compounds or into its constituent elements. Often an element such as nitrogen appears in forms that are not readily usable by organisms, and therefore such elements (which may appear individually or in compounds) need to be chemically processed through the body of a decomposer or detritivore. This processing involves chemical reactions in which the substance—whether an element or compound—is transformed into a more usable version. By processing chemical compounds from the air, water, and geosphere, decomposers and detritivores deposit nutrients in the soil. These creatures feed on plant life, thus making possible the cycle we have described. Clearly this system, of which we have sketched only the most basic outlines, is an extraordinarily complex and well-organized one, in which every organism plays a specific role. In fact, earth scientists working in the realm of biosphere studies use the term niche to describe the role that a particular organism plays in its community. (For more about the interaction of species in a biological community, see Ecology and Ecological Stress.) http://www.scienceclarified.com/everyday/Real-Life-Chemistry-Vol-8/Ecosystems.html

Feeding Relationships Energy flows through an ecosystem in one direction. Energy flows from the sun or inorganic compounds to autotrophs and then to various heterotrophs.

Food Chains A food chain is a series of steps in which organisms transfer energy by eating and being eaten. FROM PLANTS TO CARNIVORES. As plants take up nutrients from the soil, they convert them into other forms, which provide usable energy to organisms who eat the plants. (An example of this conversion process is cellular respiration, discussed in Carbon Cycle.) When an herbivore, or plant-eating organism, eats the plant, it incorporates this energy. Chances are strong that the herbivore will be eaten either by a carnivore, a meat-eating organism, or by an omnivore, an organism that consumes both herbs and herbivores—that is, both plants and animals. Few animals consume carnivores or omnivores, at least by hunting and killing them. (Detritivores and decomposers, which we discuss presently, consume the remains of all creatures, including carnivores and omnivores.) Humans are an example of omnivores, but they are far from the only omnivorous creatures. Many bird species, for instance, are omnivorous. As nutrients pass from plant to herbivore to carnivore, the total amount of energy in them decreases. This is dictated by the second law of thermodynamics (see Energy and Earth), which shows that energy transfers cannot be perfectly efficient. Energy is not "lost"—the total amount of energy in the universe remains fixed, though it may vary with a particular system, such as an individual ecosystem—but it is dissipated, or directed into areas that do not aid in the transfer of energy between organisms. What this means for the food web is that each successive level contains less energy than the levels that precede it. http://www.scienceclarified.com/everyday/Real-Life-Chemistry-Vol-8/Ecosystems.html

Food Web A food web links all the food chains in an ecosystem together.

Trophic Level Each step in a food chain or a food web is called a trophic level. Producers make up the first trophic level. Consumers make up the 2nd, 3rd, 4th & 5th levels. There are rarely more than 4 or 5 levels

Ecological Pyramids Diagrams that show the relative amounts of energy or matter contained within each trophic level. Now would be a great time to stop and remind them about food pyramids and ask them questions about their food pyramids.

Energy Pyramid Energy pyramid- shows the relative amount of energy available at each trophic level. Only about 10% of the energy available within one trophic level is transferred to organisms at the next trophic level. - This is why there are rarely more than 4 or 5 levels

Ecological pyramids show the decreasing amounts of energy, living tissue, or number of organisms at successive feeding levels. The pyramid is divided into sections that represent each trophic level. Because each trophic level harvests only about one tenth of the energy from the level below, it can support only about one tenth the amount of living tissue. http://raxacollective.files.wordpress.com/2011/08/energy_pyramid.png

Biomass Pyramid Represents the amount of potential food available for each trophic level. Expressed as grams per unit area. The greatest biomass is at the base of the pyramid.

Pyramid of numbers Shows the relative number of individual organisms at each trophic level.